Propellants based on nitrocellulose show a high combustion rate. For this reason, these propellants are predominantly used in gas generators for belt tensioners. A disadvantage in nitrocellulose propellants is, however, their poor resistance to aging. In addition, these propellants, owing to their extremely negative oxygen balance, release, on burning, large amounts of incompletely oxidized reaction products, in particular carbon monoxide.
U.S. Pat. No. 5,538,567 discloses a gas-generating composition of approximately 55 to 75% by weight guanidine nitrate, approximately 25 to 45% by weight of an oxidator, in particular potassium perchlorate, approximately 0.5 to 5% by weight of a flow improver such as graphite or soot and up to 5% by weight of a binding agent such as calcium resinate. The average particle size of the guanidine nitrate amounts to between approximately 75 and 350 μm, and the average particle size of the oxidator is between approximately 50 and 200 μm.
U.S. Pat. No. 5,854,442 describes a gas-generating composition of approximately 30 to 45% by weight potassium perchlorate, between approximately 55 and 70% by weight guanidine nitrate and 1 to 3% by weight cellulose acetate butyrate as binding agent. The particle size of the oxidator is to lie between 15 and 20 μm.
The compositions described above, owing to their chemical and physical properties, are only suitable for use in driver's or passenger's gas generators.